Astronomers first noticed the strange behaviors of rotating galaxies almost 100 years ago, suggesting there’s an invisible dark matter hold them together with gravity. Or maybe we just don’t understand how gravity works at the largest scales. Observations are much better now, and astronomers have found examples of galaxies that almost entirely made of dark matter. Does this tell us anything?
Ep. 668: The Crisis in Cosmology
Astronomers have made extremely accurate measurements of the expansion rate of the Universe and come up with different results. And the error bars for the observations don’t overlap, so there’s something strange going on. What’s the answer and how can the Crisis in Cosmology be resolved?
Ep. 667: JWST First Science Results
Astronomers came together in January to present their newest research, and not surprisingly, the Winter AAS meeting was heavy on news from JWST. What were some of the new results that were announced?
Ep. 650: First Light for JWST
Well, this is it, we’re finally going to talk about the James Webb Space Telescope. After decades of development, delays and budget creep, the powerful infrared observatory is at its final home at the L2 Lagrange Point. Yesterday we saw the first scientific images from the telescope, and according to Pamela’s rules, we’re finally allowed to talk about it.
Ep. 634: Milky Way’s Mergers & Acquisitions
The Milky Way is a vast grand spiral today, but how did it get this way? Astronomers are starting to unravel the history of our galaxy, revealing the ancient collisions with dwarf galaxies, and how they came together to build the Milky Way.
Ep. 625: End of the Year Review
We’ve reached the end of 2021, and this is the last episode of the year. Let’s look back at the big space events of the last year and talk about what we’re looking forward to in 2022.
Ep. 520: Transients: What They Are and Why They Matter, Part 2
This is our second episode in a two part series where we look at Transients in astronomy. In last week’s episode, we talked about things that change here in our own Solar System. Now we’ll talk about everything else in the Milky Way and beyond.
Ep. 498: Dwarf Galaxy Update
The Milky Way has gobbled up dozens of dwarf galaxies and added them to its structure. Today we’re going to look at the ongoing hunt for the wreckage of past mergers. And what we’ve discovered about dwarf galaxies in general.
Welcome to our last episode before our summer hiatus! Don’t worry, we’ll be back in September, and will be gearing up for our 500th episode!
Ep. 497: Update on Globular Clusters
Is it globular clusters or is it globular clusters? It doesn’t matter, they’re awesome and we’re here to update you on them.
Ep 491: Exoplanet Update 2018
Finally, a big update. Have there been news in the realm of exoplanets? More news that we can possibly cover. But we’ll try our best.
Ep 490: What's New with Supernovae
Time for another update, this time we’re going to look at what’s new with supernovae. And once again, we’ve got good news, lots of new stuff to report.
Ep 488: Dark Energy: 2018 Edition
The updates continue. Last week we talked about dark matter, and this week we continue with its partner dark energy. Of course, they’re not really partners, unless you consider mysteriousness to be an attribute. Dark energy, that force that’s accelerating the expansion of the Universe. What have we learned?
Ep. 415: Temperature of the Universe
The temperature of the Universe can vary a dramatic amount from the hot cores of stars to the vast cold emptiness of deep space. What’s the temperature of the Universe now, and what will it be in the future?
Ep. 414: Navigating Far
In our last episode, we talked about what it’ll take to navigate across the Solar System. In this episode we scale things up and speculate how future civilizations will navigate to other stars and even other galaxies.
Ep. 412: The Color of the Universe
What color is the Universe? Turns out this isn’t a simple question, and one that scientists have really been unable to answer, until now!
Ep. 408: Universe Cannibalism
We’ve talked about stellar cannibalism and galactic cannibalism, but now it’s time to take this concept to its logical extreme – universe cannibalism. In the multiverse theory of physics we live in just one of a vast range of universes which might interact with each other. Let’s look for the evidence.
Ep. 407: Galactic Cannibalism
Remember when we told you that the Universe is a big place, and anything that can go wrong, inevitably does? Today we talk about what happens when galaxies come together. This is particularly pertinent because our Milky Way will collide with Andromeda in the future!
Questions Show – light speed, Andromeda galaxy, dark matter and black holes
Another week, another roundup of your questions. This week listeners asked: will reaching light speed destroy the Universe? When is Andromeda going to look really, really cool with the unaided eye? Why didn’t dark matter all turn into black holes? And there’s even more. If you’ve got a question for the Astronomy Cast team, please email it in to email@example.com and we’ll try to tackle it for a future show.
Ep. 99: The Milky Way
The Milky Way is our home. An island of stars in a universe of other galaxies. But you might be surprised to learn that astronomers have only known the Milky Way’s true nature for just a century. Let’s learn the history of discoveries about the Milky Way, and what today’s science tells us. And let’s peer into the future to learn the ultimate fate of our galaxy.
Ep. 98: Quasars
Last week we talked about galaxies in general, and hinted at the most violent and energetic ones out there: active galaxies. Quasars have been a mystery for half a century; what kind of object could throw out more radiation than an entire galaxy? A black hole, it turns out, with the mass of hundreds of millions of suns performs this feat. Let’s trace back the history of quasars, how they were first discovered and puzzled astronomers for so long. And let’s look at what we know today.
Ep. 97: Galaxies
This week we’re going to look at some of the biggest objects in the Universe: galaxies. It was the discovery of galaxies in the early 20th century that helped astronomers realize just how big the Universe is, and how far away everything is. Let’s learn how galaxies formed and how they evolve and change over time, merging with the neighbors. And what the future holds.
Ep. 72: Cosmic Rays
We’re going to return back to a long series of episodes we like to call: Radiation that Will Turn You Into a Superhero. This time we’re going to look at cosmic rays, which everyone knows made the Fantastic Four. These high-energy particles are streaming from the Sun and even intergalactic space, and do a wonderful job of destroying our DNA, giving us radiation sickness, and maybe (hopefully!) turning us into superheroes.
Ep. 68: Globular Clusters
This week we’re going to study some of the most ancient objects in the entire Universe; globular clusters. These relics of the early Universe contain hundreds of thousands of stars, held together by their mutual gravity. Since they formed together, they give astronomers a unique way to test various theories of stellar evolution.
Ep. 37: Gravitational Lensing
Astronomers are always trying to get their hands on bigger and more powerful telescopes. But the most powerful telescopes in the Universe are completely natural, and the size of a galaxy cluster. When you use the gravity of a galaxy as a lens, you can peer right back to the edges of the observable Universe.
Ep. 26: The Largest Structures in the Universe
This week we continue the story of galaxy formation, learning how groups of galaxies come together to form the biggest structures around – galaxy superclusters. And when you look at the Universe at this scale, environment is everything.